cachetools tutorial

Author: twtrubiks

README.md

@@ -280,7 +280,7 @@ Python Notes 學習筆記 📝
 
 [colorama_tutorial.py](https://github.com/twtrubiks/python-notes/tree/master/colorama_tutorial.py) - 讓 python 輸出 terminal 有顏色
 
-[marshmallow_tutorial](https://github.com/twtrubiks/python-notes/tree/master/marshmallow_tutorial) - 序列化, 反序列化, 驗證資料格式
+[cachetools_tutorial.py](https://github.com/twtrubiks/python-notes/tree/master/cachetools_tutorial.py) - cachetools 教學
 
 ## 觀念
 

cachetools_tutorial.py

@@ -0,0 +1,94 @@
+"""
+pip3 install cachetools
+
+https://pypi.org/project/cachetools/
+"""
+
+from cachetools import cached, LRUCache, TTLCache
+import time
+
+@cached(cache={})
+def ex1_cache():
+    print('no cached')
+    return 'my data'
+
+def ex1():
+    for _ in range(3):
+        print(ex1_cache())
+
+    # 手動清理快取
+    # ex1_cache.cache_clear()
+
+    # for _ in range(3):
+    #     print(ex1_cache())
+
+
+@cached(LRUCache(maxsize=10))
+def ex2_cache(count):
+    print('no cached')
+    return 'my data'
+
+def ex2():
+    print('step1...')
+    for i in range(10):
+        # 這裡沒快取  因為第一次
+        print(ex2_cache(i))
+
+    print('step2...')
+    for i in range(10):
+        # 這裡都有快取
+        print(ex2_cache(i))
+
+    print('step3...')
+    for i in range(30, 40):
+        # 快取開始失效, 因為超過 maxsize
+        print(ex2_cache(i))
+
+
+@cached(TTLCache(maxsize=5, ttl=2))
+def ex3_cache():
+    print('no cached')
+    return 'my data'
+
+def ex3():
+    for _ in range(5):
+        print(ex3_cache())
+
+    time.sleep(3)
+    # 快取失效
+
+    for _ in range(5):
+        print(ex3_cache())
+
+MY_CACHE = TTLCache(maxsize=200, ttl=2)
+
+def set_cache():
+    MY_CACHE['1'] = '1'
+    MY_CACHE['2'] = '2'
+    MY_CACHE['3'] = '3'
+
+def get_cache():
+    if MY_CACHE.get('1'):
+        print('cached')
+        print(MY_CACHE.get('1'))
+    else:
+        print('no cached')
+
+def ex4():
+    set_cache()
+
+    for _ in range(3):
+        get_cache()
+
+    print('查看目前 cache 狀態:', dict(MY_CACHE))
+    print('sleep 2.5 sec')
+    time.sleep(2.5)
+
+    # cached expired
+    get_cache()
+
+if __name__ == '__main__':
+    ex1()
+    # ex2()
+    # ex3()
+    # ex4()